1. Field of Invention
The present invention relates to a waterproof device for a drum brake, and more particularly to a waterproof device for a drum brake which can prevent noise and malfunction of a brake by stopping water from flowing into the drum brake.
2. Description of Related Art
Large-sized commercial vehicles used in for construction sites or unpaved roads are supposed to have their wheels washed (wheels and tires washed) before starting, in order to observe the rules for road contamination prevention, because the wheels or tires are covered with dirt, etc.
Wheels are usually washed in the way of removing contaminants on the wheels or tires while they pass a puddle or a wheel washer ejecting water, but contaminants may flow into the drums of the drum brakes in the wheel-washing and cause noise of the brakes and malfunction due to corrosion.
Accordingly, air drum brakes of commercial vehicles are equipped with a specific drum cover on predetermined sides to prevent foreign substances from being flowed into the inner sides of the drum and the internal parts including the linings and provide cooling performance by discharging heat; nevertheless, water and foreign substances flow into the drums and exert a bad influence on the barking performance in wheel-washing or raining.
The structure of a dust cover of the related art and the problem of the structure are described hereafter.
FIGS. 1 and 2 are views showing the structure of a dust cover of the related art mounted around the inner edge of a drum for drum brakes.
The dust cover 30 performs cooling by absorbing heat from the drum and discharging it to the outside while preventing foreign substances from flowing into the drum.
As shown in FIGS. 1 and 2, the dust cover 30 of the related art is fastened to an anchor bracket 12 supporting the shoe of the drum brake by bolts, such that it covers the inlet of the drum 10 and closes up the inside of the drum.
In particular, the inner end portion of the dust cover 30 is fastened to the anchor bracket 12 by bolts and the outer end portion is in close contact with the inner circumferential surface of the drum 10 such that foreign substances can be blocked and heat can be discharged.
The outer end portion of the dust cover 30 is simply inserted a groove 14 formed along the outer circumferential surface of the drum in close contact with the groove 14 to block foreign substances, so there is a problem in that external air can flow into the drum 10 and water flowing inside is not completely blocked.
Accordingly, there is a problem that water flows into the drum and contaminants (particles of sand, dirt, and cement etc.) flowing with the water into the drum through the gap between the outer end of the dust cover 30 and the groove 14 of the drum 10 in wheel-washing and raining.
Further, the contaminants flowing into the drum together with water cause excessive noise in operation of the drum brake or cause scoring (stripes) on the surface of the drum and the lining by sticking on the inner side of the drum, and in some cases, they cause a problem in the braking performance and make it difficult to mount/separate the drum brake in maintenance by sticking on the operation part of the drum brake.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.